Slack pawl for looms



May 13, 1958 F. A. HAMILTON SLACK PAWL FOR LOOMS filed June 15, 1956 INVENTOR fi'flfia m iZZOn gran/64% Unite rates atent SLACK PAWL FOR LOOMS Fred A. Hamilton, Easley, S. C.

Application June 15, 1956, Serial No. 591,585

3 Claims. (Cl. 139-313) This invention relates to an improved construction of slack pawl and to an improved mounting of the slack pawl relative to other parts of an otherwise conventlonal loom.

Looms having mechanisms for automatically replenishing the weft or filling upon breakage or depletion are ordinarily provided with let-back mechanisms for letting back the cloth roll take-up mechanisms to prevent thin places in the cloth when the weft or filling is replenished.

Such mechanism ordinarily includes a pair of slack pawls pivoting about a common pivot and which are disposed forwardly with respect to a ratchet wheel engaged thereby and so as to protrude into the alleyway or space between looms. Consequently, these slack pawls in such an exposed position are frequently broken off or severely damaged by quill and filling boxes which are rolled through the alleyways.

Accordingly, it is a primary object of present invention to provide an improved construction of slack pawls and an improved mounting thereof whereby the slack pawls are located in a protected position relative to other parts of the loom to prevent the slack pawls from being struck by quill and filling boxes, as previously described, and being broken off or severely damaged thereby.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawing, illustrating a presently preferred embodiment thereof, and wherein:

Figure 1 is a fragmentary front elevational view of a portion of a loom and illustrating the improved mounting of the slack pawls;

Figure 2 is an enlarged fragmentary side elevational view of the let-back mechanism looking from right to left of Figure 1 and more clearly illustrating the disposition of the slack pawls which form a part thereof, relative to other portions of said mechanism, and

Figure 3 is an enlarged fragmentary side elevational View, partly in section looking toward the opposite side of the let-back mechanism.

Referring more specifically to the drawing, a portion of a conventional loom is illustrated in the drawing and is designated generally 5, including a part of the loom frame 6 and which includes an intermediate vertical frame member or cloth roll stand 7. The loom includes a driven shaft 8 on which is mounted a pinion 9 which is connected to and driven in unison with the shaft 8 by a clutch 10 for driving a train of gears 9 by which the take-up roll, not shown, of the loom is driven.

A ratchet wheel 11 is formed integral with or secured to the right-hand side of the pinion 9, or the side thereof located opposite to the clutch 10. Said ratchet wheel 11 constitutes a part of the let-back mechanism, designated generally 12 and best illustrated in Figures 2 and 3. The let-back mechanism 12 includes a pawl carrier 13 which is disposed on the other or right-hand side of the ratchet wheel 11 and which includes a hub portion 14 which is journalled on the end portion 8' of the shaft 8 and which has an arm 15 extending upwardly from the hub 14. The arm 15 is provided at its outer end with a laterally extending sleeve 16 which partially overlies and is spaced outwardly from a portion of the ratchet wheel 11. The pawl carrier 13 also includes a short arm 17 which terminates in a weight 18. The arm 17 is disposed at an obtuse angle to the arm 15 and extends forwardly from the hub 14, so that the weight 18 is disposed forwardly of the shaft 8, as seen in Figures 2 and 3.

An arm 19 is rigidly fastened at 20 to the intermediate frame member 7 and extends forwardly therefrom across the right-hand side of the pawl carrier arm 15, so that said arm 15 is disposed between a portion of the arm 19 and the ratchet wheel 11. The free end portion of the arm or pawl stop 19 is provided with an arcuate slot 21 to loosely receive a pin or stud 22 which is fixed to and extends laterally from the carrier arm 15 and which is movable in the slot 21. The outer portion of the pawl stop 19 is provided with openings 23 which open into the slot 21, which are disposed in the plane of the pawl stop 19, and pairs of which align to selectively receive a stop pin 24 which extends across the slot 21 and which may be selectively positioned in different pairs of the openings 23 for spacing the stop pin 24 different distances from the ends of the slot 21.

A pair of slack pawls 25 and 26 is carried by the outer end of the carrier arm 15 for swinging movement therewith and relative thereto by a headed pivot pin 2'7 which extends loosely through corresponding shank ends 28 of the pawls 25' and 26 and then through the sleeve 16 from left to right as seen in Figure 1 or in a direction away from the plane of the ratchet wheel 11, for pivotally mounting the pawls 25 and 26 relative to the arm 15 and directly over the ratchet wheel 11, as seen in Figure l.

The teeth 11 of the ratchet wheel 11 are all inclined in a clockwise direction as seen in Figure 2, as is conventional. The slack pawls 25 and 26 instead of extending forwardly from the carrier arm sleeve 16, as is conventional, extend rearwardly therefrom as best illustrated in Figures 2 and 3. Said pawls Z5 and 26 are each formed from a strip of metal which is twisted adjacent an end thereof to form the shank end 28. Thus, the shank ends 28 of the pawls 25 and 26 are disposed in substantially parallel abutting relation to one another as seen in Figure 1. The pawls 25 and 26 have substantially hook-shaped opposite free ends 29 and 30, respectively. The hook-shaped free end 29 of the pawl 25 is larger than the hook-shaped free end 30 of the pawl 26 and said pawl 25 is longer than the pawl 26. Said inwardly extending hook-shaped ends 29 and 30 have substantially straight terminal portions 31 and 32, respectively, the distal ends of which engage the ratchet teeth 11'. The longer pawl 25 is disposed with its hook portion 29 overlying and spaced outwardly from the hook portion 39 of the shorter pawl 26 and the terminal 31 thereof engages a tooth 11' disposed below the tooth engaged by the terminal 32 of the slack pawl 26.

From the foregoing it will be apparent that the letback mechanism 12 as heretofore described and as illustrated in the drawing differs from a conventional loom let-back mechanism in that the slack pawls are differently constructed and are differently mounted to extend rearwardly rather than forwardly from the slack pawl carrier with respect to the loom. Thus, the slack pawls 25 and 26 are disposed in protected positions behind rather than in front of the ratchet wheel 11, in which positions the slack pawls 25 and 26 are effectively protected from being struck by quill boxes and filling boxes being rolled across the front of the loom 5.

The slack pawls 25 and 26 function in a conventional manner in that said slack pawls do not affect the normal operation of the loom in connection with which the shaft of the weft is to be accomplished, the clutch 10 is disengaged for disengaging the pinion 9 and ratchet wheel 11 from the shaft 8 to permit said pinion and ratchet wheel and the gear train 9' to turn with the take-up roll to accomplish the let-back or slackening of the cloth to cover defects which might result from the bobbin change. In accomplishing the let-back operation, the ratchet wheel 11 and pinion 9 turn in the opposite direction or clockwise as seen in Figure 2 and relative to the shaft 8. The extent that the ratchet wheel 11 can turn clockwise is restricted to the distance between the stud 22 and the inner end of the slot 21, as during the let-back operation the pawl carrier 13 and slack pawls 25 and 26 turn clockwise as seen in Figure 2 with the ratchet wheel 11 and until the stud 22 engages the inner end of the slot 21. Thus, adjustment of the pin 24 relative to the inner or rear end of the slot 21 varies the extent of let-back since the weight 18 always maintains the stud 22 against the stop pin 24 except during let-back.

Various modifications and changes are contemplated and may obviously be resorted to without departing from the function or scope of the invention as hereinafter defined by the appended claims.

I claim as my invention:

1. In a loom, a let-back mechanism comprising a ratchet wheel, a slack pawl carrier, a shaft on which the ratchet wheel and carrier are mounted to turn during the let-back operation, said carrier including an arm extending upwardly from the shaft, a pair of slack pawls, means pivotally mounting said slack pawls on the outer end of said arm for pivotal movement relative to the arm about a common pivot, a stationary slack pawl stop, means forming a loose connection between the slack pawl carrier and slack pawl stop for limiting swinging movement of the carrier about said shaft, said carrier including a weight for'urging the carrier and slack pawls to swing in a direction opposite to the direction of swinging movement thereof during the let-back operation, said ratchet wheel being disposed in a forward position relative to the loom, and said slack pawls extending rearwardly from the pivot thereof and having inturned forwardly extending free ends engaging teeth ot'the ratchet wheel whereby the free ends of the slack pawls are disposed behind the ratchet wheel, said slack pawls including a long pawl and a short pawl, each of said pawls being formed from a strip of metal, said pawl forming strips having twisted substantially corresponding ends disposed in substantially abutting engagement and in planes substantially corresponding to the plane of the ratchet wheel and forming shank ends of the pawls, said shank ends being engaged by the pawl pivot.

2. In a loom let-back mechanism as in claim 1, the twisted shank ends of said pawls being disposed substantially at right angles to the remainder of the pawls, said pawls including hook shaped portions having terminals constituting said free ends of the pawls.

3. In a loom let-back mechanism as in claim 2, the hooked shaped portion of the long pawl overlying and being spaced outwardly from the hook shaped portion of the short pawl and the terminal thereof engaging a tooth of the ratchet wheel disposed below a ratchet wheel tooth engaged by the terminal of the short pawl.

References Cited in the file of this patent UNITED STATES PATENTS 1,647,234 La Chapelle Nov. 1, 1927 1,794,420 Robellard Mar. 3, 1931 2,551,910 Sprouse May 8, 1951 FOREIGN PATENTS 12,195 Great Britain Sept. 17, 1914 121,895 Great Britain Jan. 9, 1919 

